A semiconductor manufacturing process may include a wafer level packaging (WLP) technique which processes a wafer into complete semiconductor packages. In this technique, rewiring, resin sealing and bump soldering, which are required for the semiconductor packages, are performed for the wafers in which ICs are fabricated, and the wafer is segmentalized into the semiconductor packages up to the same size as an IC chip.
In typical LSI manufacturing, a pre-process is followed by a post-process including back grinding to polish and thin a wafer, dicing to segmentalize the wafer or cut off the wafer into chips, mounting to mount the chips on a pad, adhesion, molding, finishing, testing, etc. On the other hand, SiP (System in Package) (which is a kind of WLP) manufacturing includes an intermediate process between a pre-process and a post-process. The intermediate process may include a rewiring process to process an upper part of the wirings of a chip between receipt of a wafer processed in the pre-process and back grinding. In addition, an interlayer insulating film is formed using a polyimide or the like, a Cu wiring is formed, and soldering balls are mounted on a leading end of the Cu wiring.
Since wafer polishing and the like are required after the intermediate process, care is required in the thickness, bending, the heating treatment temperature and so on of the wafer.
When the interlayer insulating film is formed using the polyimide, the polyimide is heated and cured. However, in a heating and curing process using a conventional resistive heater, it is not easy to prevent the wafer from being bent since the wafer is hot per se. Accordingly, there is a desire for a technique capable of heating and curing a polyimide while keeping a wafer at a low temperature.
A semiconductor manufacturing process may also include a CVD (Chemical Vapor Deposition) process which subjects a surface of a substrate (a target substrate having a silicon wafer or glass as a base and including fine patterns of electrical circuits formed thereon) to a predetermined film forming process. In this CVD process, the substrate is loaded into an airtight reaction chamber and heated by a heating means disposed in the reaction chamber to cause a chemical reaction while introducing film forming gas onto the substrate, so that a film can be uniformly formed on a fine pattern of electrical circuits formed on the substrate. With such a CVD process, for example, organic chemical material may be used as a film forming raw material to form a high-k (high dielectric) film, which is an insulating film having a relatively large dielectric constant such as a ZrO (zirconia) film or the like.
However, since a ZrO film contains a large quantity (several percentages (%)) of impurities such as CH, OH and the like, which are produced due to the organic material, its electrical insulation is insufficient. For the purpose of securing electrical insulation and stabilization of this thin film, an attempt has been made to subject a ZrO film to a fast annealing process in a temperature range of 650 degrees C. to 800 degrees C. under an oxygen (O2) or nitrogen (N2) atmosphere to remove impurities such as carbon (C), hydrogen (H) and the like from the film to densify the film, thereby modifying the film into a stable insulating film. This densification is performed to shorten an average interatomic distance in an amorphous state without leading to crystallization. In such a fast annealing process, the entire substrate is heated to a predetermined temperature to modify the ZrO film.
Meanwhile, in recent semiconductor devices, shallow junctions are widely used for device miniaturization and there is a need for a small thermal budget (heat history). Accordingly, even in the annealing process used in the above-described high-film forming process, there is a need to densify a high-k film by heating the high-k film while keeping a substrate at a low temperature, and removing impurities from the high-k film, thereby achieving a small thermal budget. The reason for keeping the substrate at a low temperature is as follows: in some device manufacturing processes, if the substrate is processed in a post-process at a temperature higher than that in a pre-process, a device already established in the pre-process may be collapsed or a characteristic of a film may be varied. Therefore, the process temperature in the post-process cannot exceed that in the pre-process. Accordingly, there is a desire for a technique capable of performing a film reforming process at a low temperature for the enhancement of device performance In the related art, there is known a technique for forming a high dielectric film, which contains hafnium, on a substrate in a film forming process, and then supplying argon radicals onto the substrate and removing impurity elements from the high dielectric film in a modifying process.